Magnetic resonance imaging (MRI) apparatuses are configured to excite nuclear spins of an object placed in a static magnetic field with use of a radio frequency (RF) pulse having the Larmor frequency and to reconstruct magnetic resonance signals generated from the object with the excitation to thereby generate images. Unlike X-ray CT apparatuses and the like, the object is not exposed to radiation, so that diagnostic imaging can be performed in a less invasive manner.
The MRI apparatuses acquire an image by repeatedly applying an RF pulse and a gradient magnetic field to the object based on a pulse sequence. However, when the pulse sequence is executed, the magnetic field in an imaging space that houses the object is changed and causes generation of an eddy current. With the generation of the eddy current, a magnetic field different from the magnetic field set by the pulse sequence may be applied to the object. When the magnetic field being different from the magnetic field set by the pulse sequence is applied to the object, noise and sensitivity unevenness occur in acquired images, which may cause deterioration of image quality.
Accordingly, an MRI apparatus is provided which performs imaging (hereinafter referred to as a prescan) before performing imaging (hereinafter referred to as a main scan) that acquires an image for use in actual diagnostic imaging. The prescan is performed to acquire correction values for correcting a pulse sequence used in the main scan.
However, to acquire the correction values in the prescan, a pulse sequence that is same type to the pulse sequence used in the main scan needs to be executed in the prescan. Since one imaging action is constituted of a prescan and a main scan, the entire imaging time increases as execution of the prescan takes longer time.